fix(2.0): GPU-Metrik findet Strix-Halo-Card dynamisch (card1) + GTT

Real-Box-Befund: GPU ist card1 (nicht hardcoded card0), Connector-Dirs
uebersprungen. Zusaetzlich GTT (echter Unified-Memory-Pool) statt nur
VRAM-Carve-out. Frontend zeigt GTT bevorzugt.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/lib/api.ts

@@ -83,7 +83,13 @@ export interface RoutingResp {
 export interface SystemStatus {
   cpu: { percent: number; cores: number | null }
   ram: { total: number; used: number; percent: number }
-  gpu: { busy_percent: number | null; vram_used: number | null; vram_total: number | null } | null
+  gpu: {
+    busy_percent: number | null
+    vram_used: number | null
+    vram_total: number | null
+    gtt_used?: number | null
+    gtt_total?: number | null
+  } | null
   temp: { cpu?: number; gpu?: number } | null
   disk: { total: number; used: number; percent: number } | null
 }